1. Field of the Invention
This invention is for multiple safety valves for location within an oil or gas well that can be activated to open or close and thus prevent, or permit upward flow of fluids within the well for example in case of an emergency.
2. Description of Related Art
Downhole safety valves are known that include a housing, a flapper valve and a remotely controlled actuator for closing the normally open valve in case of an emergency. See for example U.S. Pat. No. 7,392,849. Also serially arranged valves in a downhole tool are also known. Examples of such are shown in U.S. Pat. Nos. 6,394,187; 7,673,689; 4,846,281; 4,605,070; and 6,152,229. These valves are complicated in design and are not compact as is critical in the art. Furthermore the internal flow passage for the fluids are not of a single diameter and many contain obstruction shoulders or changes in diameter that result in turbulent flow or pressure drops.
Threaded joints are in common use in hydrocarbon producing wells. During design qualification of subsurface safety valves, a body joint must be designed qualified and verified which is an expensive process, because of the consequences of a leak in a valve of this type. Typical solutions would be to provide valves with two body joints and a pup joint between which adds two additional body joints. The present invention reduces the number of body joints in an integral valve to four or five and utilizes the same body joint.